Utilizzo di tecnologie avanzate per applicazioni di "high speed cooking"

The microwave (MW) technology has become crucial in "high speed cooking" equipment. This new generation of cooker is still being refined and still finding its place in today's kitchens, but it is clear that these new high speed ovens can cook a wide variety of products and cook them faster than anything previously on the market. In ordinary cooking, heat is applied to the outside of food and it gradually penetrates to the inside. In MW cooking, the heat is generated within the food. Thus, a shorter heating time and a higher efficiency are some of the benefits of this technology. MW cooking is rapid, but non-uniform. MW heating is non-uniform mainly because of the inherently uneven distribution of the electromagnetic (EM) field inside the oven cavity. As the energy penetrates a lossy material, it is absorbed and less of it remains to penetrate further. Thus, energy absorption is non-uniform. Moreover, the energy absorption process is strongly affected by shape, size, dielectric properties of materials, position of the workload, as well as by the cavity geometry and dimensions. MW heating systems must provide uniform heating to obtain high quality products and avoid the so-called hot spots and cold spots. Traditionally, the temperature uniformity is accomplished by moving parts within the applicator, using mode stirrers, employing turntable or a combination of these techniques. Unfortunately, these techniques are not applicable within all type of resonant cavities. Other techniques which do not involve moving parts are: the pulsing MW energy or the phase shifting for different sources of MW energy. The phase shift technique and its effects on the EM field distribution and heating of a workload is discussed in the Thesis. The study of MW power sources has increased popularity among researchers in the field of cooking systems. In the last few years the innovative high frequency power solid state devices has gained much attention in place of magnetron due to their higher performances. In particular, a more careful control of the cooking process, which guarantees a more uniform heating of the foodstuff, can be achieved by using the solid state devices. This result can be reached, for instance, by using a properly phase shift for different sources of MW energy and it is discussed in the Thesis. Another solution, that is examined, involves the use of slots in the waveguide wall, which radiate EM energy from the waveguide. Since a multi slotted waveguide can be considered as an antenna array, a proper design of the slotted waveguide antennas, which feed the launch box and the MW applicator, is proposed in order to attain a more uniform temperature distribution without the need of moving parts. The effectiveness of the aforementioned technical solutions has been verified by means of numerical simulations on a test case model of practical interest, named "panini grill". The use of MW technology ensures a sandwich is heated through without a cold centre while reducing cooking time significantly. In the 3D numerical model two physical phenomena, i.e. EM wave propagation and heat transport, are coupled together by the thermal effects of MW energy deposition and the temperature-dependent material parameters. The coupled problem is solved by means of a FEA commercial software (COMSOL). In order to achieve the design parameters for the slotted waveguide feeding system and the phase shifting, which guarantee the more uniform hating, an optimization problem has been solved. More specifically, a metamodels-based optimization method has been set up. The metamodels can significantly reduce the problem complexity and simulation time. The optimization procedure has been characterized by pre-processing, programming, and post-processing coupling COMSOL Multiphysics and Matlab software

Liver transplantation for viral hepatitis in 2015

Liver transplantation (LT) is a life-saving treatment for patients with end-stage liver disease and for patients with liver cell cancer related to liver disease. Acute and chronic liver diseases related to hepatitis viruses are between the main indications for liver transplantation. The risk of viral reinfection after transplantation is the main limiting factor in these indications. Before the availability of antiviral prophylaxis, hepatitis B virus (HBV) recurrence was universal in patients who were HBV DNA-positive before transplantation. The natural history of recurrent HBV was accelerated by immunosuppression, and it progressed rapidly to graft failure and death. Introduction of post-transplant prophylaxis with immunoglobulin alone first, and associated to antiviral drugs later, drastically reduced HBV recurrence, resulting in excellent long-term outcomes. On the contrary, recurrence of hepatitis C is the main cause of graft loss in most transplant programs. Overall, patient and graft survival after LT for hepatitis C virus (HCV)-associated cirrhosis is inferior compared with other indications. However, successful pretransplant or post transplant antiviral therapy has been associated with increased graft and overall survival. Until recently, the combination of pegylated interferon and ribavirin was the standard of care for the treatment of patients with chronic hepatitis C. Highly active antiviral compounds have been developed over the past decade, thanks to new in vitro systems to study HCV entry, replication, assembly, and release

Hepatitis C virus related cirrhosis decreased as indication to liver transplantation since the introduction of direct-acting antivirals: A single-center study

AIM: To evaluate waiting list (WL) registration and liver transplantation (LT) rates in patients with hepatitis C virus (HCV)-related cirrhosis since the introduction of direct-acting antivirals (DAAs). METHODS: All adult patients with cirrhosis listed for LT at Padua University Hospital between 2006-2017 were retrospectively collected using a prospectively-updated database; patients with HCV-related cirrhosis were divided by indication for LT [dec-HCV vs HCV/ hepatocellular carcinoma (HCC)] and into two interval times (2006-2013 and 2014-2017) according to the introduction of DAAs. For each patient, indications to LT, severity of liver dysfunction and the outcome in the WL were assessed and compared between the two different time periods. For patients receiving DAA-based regimens, the achievement of viral eradication and the outcome were also evaluated. RESULTS: One thousand one hundred and ninty-four [male (M)/female (F): 925/269] patients were included. Considering the whole cohort, HCV-related cirrhosis was the main etiology at the time of WL registration (490/1194 patients, 41%). HCV-related cirrhosis significantly decreased as indication to WL registration after DAA introduction (from 43.3% in 2006-2013 to 37.2% in 2014-2017, P = 0.05), especially amongst dec-HCV (from 24.2% in 2006-2013 to 15.9% in 2014-2017, P = 0.007). Even HCV remained the most common indication to LT over time (289/666, 43.4%), there was a trend towards a decrease after DAAs introduction (from 46.3% in 2006-2013 to 39% in 2014-2017, P = 0.06). HCV patients (M/F: 43/11, mean age: 57.7 \ub1 8 years) who achieved viral eradication in the WL had better transplant-free survival (log-rank test P = 0.02) and delisting rate (P = 0.002) than untreated HCV patients. CONCLUSION: Introduction of DAAs significantly reduced WL registrations for HCV related cirrhosis, especially in the setting of decompensated cirrhosis

Management of bacterial infection in the liver transplant candidate

Bacterial infection (BI) is a common cause of impairment of liver function in patients with cirrhosis, especially in the liver transplant candidates. These patients share an immunocompromised state and increased susceptibility to develop community and hospital-acquired infections. The changing epidemiology of BI, with an increase of multidrug resistant strains, especially in healthcare-associated settings, represents a critical issue both in the waiting list and in the post-operative management. This review focused on the role played by BI in patients awaiting liver transplantation, evaluating the risk of drop-out from the waiting list, the possibility to undergo liver transplantation after recovery from infection or during a controlled infection

Neuropsychiatric performance and treatment of hepatitis C with direct-acting antivirals: a prospective study

Background: Since direct-acting antivirals (DAAs) have been approved for the treatment of hepatitis C virus (HCV) infection, a small series of patients with new-onset neuropsychiatric alterations have been referred to us. We therefore set out to study neuropsychiatric function in relation to DAAs prospectively. Methods: Ten patients with cirrhosis and 12 post-liver transplant (post-LT) patients were enrolled. All underwent wake electroencephalography (EEG) and a neuropsychological evaluation (paper and pencil battery, simple/choice reaction times, working memory task) at baseline, at the end of treatment with DAAs and after 6 months. At the same time points, full blood count, liver/kidney function tests, quantitative HCV RNA, ammonia and immunosuppressant drug levels were obtained, as appropriate. Results: Patients with cirrhosis were significantly older than post-LT patients (65\ub112 vs 55\ub17 years; P<0.05). Neuropsychological performance and wake EEG were comparable in the two groups at baseline. At the end of a course of treatment with DAAs, a significant slowing in choice reaction times and in the EEG (increased relative delta power) was observed in patients with cirrhosis, which resolved after 6 months. In contrast, no significant changes over time were observed in the neuropsychiatric performance of post-LT patients. No significant associations were observed between neuropsychiatric performance and stand-alone/combined laboratory variables. Conclusion: Some degree of neuropsychiatric impairment was observed in relation to treatment with DAAs in patients with cirrhosis, but not in post-LT patients, suggesting that the former may be sensitive to mild DAA neurotoxicity

Polyclonal and monoclonal B lymphocytes response in HCV-infected patients treated with direct-acting antiviral agents

Hepatitis C virus (HCV) chronic infection can be associated with extrahepatic manifestations such as mixed cryoglobulinaemia and lymphoproliferative disorders that are endowed with increased rates of morbidity and all-cause mortality. In this study, we used flow cytometry to evaluate the effect of interferon-free antiviral treatment on peripheral blood lymphocytes in HCV-infected patients with or without associated lymphoproliferative disorders. Flow cytometry analysis of peripheral blood lymphocytes was performed at baseline and at the end of treatment. In HCV-infected patients with lymphoproliferative disorders, we evaluated immunoglobulin (Ig) light chain \u3ba/\u3bb ratio variations as a measure of monoclonal B-cell response to antiviral therapy. Healthy volunteers were enrolled as controls. A total of 29 patients were included, nine with and 20 without lymphoproliferative disorders. Sustained virological response was achieved in 29 of 29 patients. We observed a significant reduction in the B-cell compartment (39% global reduction) in eight of nine HCV-infected patients with lymphoproliferative disorders after viral clearance. We recognized the same trend, even if less pronounced, in HCV-infected patients without lymphoproliferative disorders (9% global reduction). Among HCV-infected patients with lymphoproliferative disorders, three showed an improvement/normalization of the immunoglobulin light chain ratio, whereas in the remaining six patients monoclonal B cells persisted to be clonally restricted even 1\ua0year after the end of treatment. Our data show that DAAs treatment can be effective in reducing the frequency of pathological B cells in the peripheral blood of HCV-infected patients affected by HCV-associated lymphoproliferative disorders; however, monoclonal populations can persist after viral eradication

Drop-out rate from the liver transplant waiting list due to HCC progression in HCV-infected patients treated with direct acting antivirals.

BACKGROUND & AIM: concerns about an increased hepatocellular carcinoma (HCC) recurrence rate following directly acting antiviral (DAA) therapy in cirrhotic patients with a prior complete oncological response have been raised. Data regarding the impact of HCV-treatment with DAAs on waiting list drop-out rates in patients with active HCC and HCV-related cirrhosis awaiting liver transplantation (LT) are lacking. MATERIALS AND METHODS: HCV-HCC patients listed for LT between January 2015 and May 2016 at Padua Liver Transplant Centre were considered eligible for the study. After enrollment patients were divided into 2 groups, depending on whether they underwent DAAs treatment while awaiting LT or not. For each patient clinical, serological and virological data were collected. HCC characteristics were radiologically evaluated at baseline and during follow-up (FU). For transplanted patients, pathological assessment of the explants was performed and recurrence-rates were calculated. RESULTS: twenty-three patients treated with DAAs and 23 controls were enrolled. HCC characteristics at time of LT-listing were comparable between the 2 groups. Median FU was 10 and 7 months, respectively, during which 2/23 (8.7%) and 1/23 (4.3%) drop-out events due to HCC-progression were registered (p = 0.9). No significant differences in terms of radiological progression were highlighted (p = 0.16). Nine out of 23 cases (39%) and 14/23 (61%) controls underwent LT, and histopathological analysis showed no differences in terms of median number and total tumor volume of HCC nodules, tumor differentiation or microvascular invasion. During post-LT FU, 1/8 DAAs treated patient (12,5%) and 1/12 control (8,3%) experienced HCC recurrence (p = 0.6). CONCLUSIONS: Viral eradication does not seem to be associated with an increased risk of drop-out due to neoplastic progression in HCV-HCC patients awaiting LT

Platelets and Hepatocellular Cancer: Bridging the Bench to the Clinics

Growing interest is recently being focused on the role played by the platelets in favoring hepatocellular cancer (HCC) growth and dissemination. The present review reports in detail both the experimental and clinical evidence published on this topic. Several growth factors and angiogenic molecules specifically secreted by platelets are directly connected with tumor progression and neo-angiogenesis. Among them, we can list the platelet-derived growth factor, the vascular endothelial growth factor, the endothelial growth factor, and serotonin. Platelets are also involved in tumor spread, favoring endothelium permeabilization and tumor cells\u2019 extravasation and survival in the bloodstream. From the bench to the clinics, all of these aspects were also investigated in clinical series, showing an evident correlation between platelet count and size of HCC, tumor biological behavior, metastatic spread, and overall survival rates. Moreover, a better understanding of the mechanisms involved in the platelet\u2013tumor axis represents a paramount aspect for optimizing both current tumor treatment and development of new therapeutic strategies against HCC

Direct-acting antivirals and hepatocellular carcinoma in chronic hepatitis C: A few lights and many shadows

With the introduction of direct-acting antiviral agents (DAA), the rate of sustained virological response (SVR) in the treatment of hepatitis C virus (HCV) has radically improved to over 95%. Robust scientific evidence supports a beneficial role of SVR after interferon therapy in the progression of cirrhosis, resulting in a decreased incidence of hepatocellular carcinoma (HCC). However, a debate on the impact of DAAs on the development of HCC is ongoing. This review aimed to analyse the scientific literature regarding the risk of HCC in terms of its recurrence and occurrence after the use of DAAs to eradicate HCV infection. Among 11 studies examining HCC occurrence, the de novo incidence rate ranged from 0 to 7.4% (maximum follow-up: 18 mo). Among 18 studies regarding HCC recurrence, the rate ranged from 0 to 54.4% (maximum "not well-defined" followup: 32 mo). This review highlights the major difficulties in interpreting data and reconciling the results of the included studies. These difficulties include heterogeneous cohorts, potential misclassifications of HCC prior to DAA therapy, the absence of an adequate control group, short follow-up times and different kinds of follow-up. Moreover, no clinical feature-based scoring system accounts for the molecular characteristics and pathobiology of the tumours. Nonetheless, this review does not suggest that there is a higher rate of de novo HCC occurrence or recurrence after DAA therapy in patients with previous HCV infection. \ua9 2018 The Author(s). Published by Baishideng Publishing Group Inc. All rights reserved

Platelets and hepatocellular cancer: Bridging the bench to the clinics

Growing interest is recently being focused on the role played by the platelets in favoring hepatocellular cancer (HCC) growth and dissemination. The present review reports in detail both the experimental and clinical evidence published on this topic. Several growth factors and angiogenic molecules specifically secreted by platelets are directly connected with tumor progression and neo-angiogenesis. Among them, we can list the platelet-derived growth factor, the vascular endothelial growth factor, the endothelial growth factor, and serotonin. Platelets are also involved in tumor spread, favoring endothelium permeabilization and tumor cells' extravasation and survival in the bloodstream. From the bench to the clinics, all of these aspects were also investigated in clinical series, showing an evident correlation between platelet count and size of HCC, tumor biological behavior, metastatic spread, and overall survival rates. Moreover, a better understanding of the mechanisms involved in the platelet-tumor axis represents a paramount aspect for optimizing both current tumor treatment and development of new therapeutic strategies against HCC